微信小程序 base64 图片 绘制canvas

下载https://github.com/Pudon/weapp-qrcode-base64

const imgData = QRCode.drawImg('二维码信息', {

typeNumber: 4,

errorCorrectLevel: 'M',

size: 500

})

this.qrcodePath = imgData

const fsm = wx.getFileSystemManager();

const FILE_BASE_NAME = 'tmp_base64src';

//写文件时去掉 base64 的头信息否则绘制不出来

const [, format, bodyData] = /data:image\/(\w+);base64,(.*)/.exec(imgData) || [];

const filePath = `${wx.env.USER_DATA_PATH}/${FILE_BASE_NAME}.${format}`;

const buffer = wx.base64ToArrayBuffer(bodyData);

fsm.writeFile({

filePath,

data: buffer,

encoding: 'binary',

success:() => {

console.log(filePath);

const ctx = uni.createCanvasContext('customCanvas')

ctx.drawImage(filePath, 180*rpx, 200*rpx, 140* rpx, 140* rpx)

}

});